diff options
| -rw-r--r-- | include/linux/kernel.h | 2 | ||||
| -rw-r--r-- | kernel/extable.c | 16 | ||||
| -rw-r--r-- | kernel/notifier.c | 8 | ||||
| -rw-r--r-- | kernel/softlockup.c | 2 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 10 |
5 files changed, 37 insertions, 1 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 2651f805ba6d..3f30557be2a3 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -187,6 +187,8 @@ extern unsigned long long memparse(char *ptr, char **retptr); extern int core_kernel_text(unsigned long addr); extern int __kernel_text_address(unsigned long addr); extern int kernel_text_address(unsigned long addr); +extern int func_ptr_is_kernel_text(void *ptr); + struct pid; extern struct pid *session_of_pgrp(struct pid *pgrp); diff --git a/kernel/extable.c b/kernel/extable.c index a26cb2e17023..adf0cc9c02d6 100644 --- a/kernel/extable.c +++ b/kernel/extable.c @@ -66,3 +66,19 @@ int kernel_text_address(unsigned long addr) return 1; return module_text_address(addr) != NULL; } + +/* + * On some architectures (PPC64, IA64) function pointers + * are actually only tokens to some data that then holds the + * real function address. As a result, to find if a function + * pointer is part of the kernel text, we need to do some + * special dereferencing first. + */ +int func_ptr_is_kernel_text(void *ptr) +{ + unsigned long addr; + addr = (unsigned long) dereference_function_descriptor(ptr); + if (core_kernel_text(addr)) + return 1; + return module_text_address(addr) != NULL; +} diff --git a/kernel/notifier.c b/kernel/notifier.c index 823be11584ef..0f39e398ef60 100644 --- a/kernel/notifier.c +++ b/kernel/notifier.c @@ -82,6 +82,14 @@ static int __kprobes notifier_call_chain(struct notifier_block **nl, while (nb && nr_to_call) { next_nb = rcu_dereference(nb->next); + +#ifdef CONFIG_DEBUG_NOTIFIERS + if (unlikely(!func_ptr_is_kernel_text(nb->notifier_call))) { + WARN(1, "Invalid notifier called!"); + nb = next_nb; + continue; + } +#endif ret = nb->notifier_call(nb, val, v); if (nr_calls) diff --git a/kernel/softlockup.c b/kernel/softlockup.c index cb838ee93a82..b9a528f22736 100644 --- a/kernel/softlockup.c +++ b/kernel/softlockup.c @@ -164,7 +164,7 @@ unsigned long __read_mostly sysctl_hung_task_check_count = 1024; /* * Zero means infinite timeout - no checking done: */ -unsigned long __read_mostly sysctl_hung_task_timeout_secs = 120; +unsigned long __read_mostly sysctl_hung_task_timeout_secs = 480; unsigned long __read_mostly sysctl_hung_task_warnings = 10; diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 0b504814e378..4116e10ea14a 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -536,6 +536,16 @@ config DEBUG_SG If unsure, say N. +config DEBUG_NOTIFIERS + bool "Debug notifier call chains" + depends on DEBUG_KERNEL + help + Enable this to turn on sanity checking for notifier call chains. + This is most useful for kernel developers to make sure that + modules properly unregister themselves from notifier chains. + This is a relatively cheap check but if you care about maximum + performance, say N. + config FRAME_POINTER bool "Compile the kernel with frame pointers" depends on DEBUG_KERNEL && \ |